1. Technical Field
The present invention relates to a laser projector.
2. Related Art
There is a known scan-type projector of related art as an image display apparatus capable of displaying a large screen image. A scan-type projector displays an image by raster scanning a screen or any other projection surface with modulated laser light. Laser light, which is single-wavelength light and hence has high degrees of color purity and coherency, is characterized, for example, in that a laser beam is readily shaped. An image display apparatus that displays an image by using laser light can therefore provide significantly increased contrast, color reproducibility, resolution, and other performance factors.
In recent years, there is a known projector that has a light diffusing device disposed therein, forms an image based on modulated laser light as an intermediate image in the light diffusing device, and enlarges and projects the intermediate image through a projection lens (JP-A-2006-53495, for example). The thus configured projector forms a laser projector that is compact and produces a reduced amount of speckle noise.
A laser light source typically used in the laser projector described above, however, has room for improvement from a viewpoint of improvement in image quality from the following reasons.
In a scan-type projector, no physical pixel such as a physical pixel of a liquid crystal device is present, and the laser light spot diameter on the projection surface or in the imaging plane where the intermediate image is formed corresponds to the size of a pixel of a projected image. That is, the smaller the spot diameter on the projection surface or in the plane where the intermediate image is formed, the higher the resolution of a displayed image. On the other hand, reduction in the spot diameter of laser light from a laser light source is limited when high priority is placed on ensuring the output power and reliability of the laser light source.